Generation and Detection of a Relatively Persistent Carboxylic Acid Enol2,2-Bis(2‘,4‘,6‘-triisopropylphenyl)ethene-1,1-diol
作者:Joseph Frey、Zvi Rappoport
DOI:10.1021/ja9601090
日期:1996.6.5
Ditipyl ketene (tipyl = 2,4,6-triisopropylphenyl) (20), ditipylacetic acid (19), and 2,2-ditipyl bis(trimethylsilyl) acetal 28 were prepared as potential precursors for the enol of 19, i.e., 2,2-di...
Reactions of the Relatively Persistent Carboxylic Acid Enol2,2-Ditipylethene-1,1-diol. The Reversibility of Ketene Hydration<sup>1</sup>
作者:Joseph Frey、Zvi Rappoport
DOI:10.1021/ja960456+
日期:1996.6.5
benzopyranone (9), formed by cyclization on an o-i-Pr group and ring bromination. No product resulting from reaction of bromine with the double bond was formed. This is ascribed to shielding of the double bond by steric crowding. Attempted etherification of the enolic OH groups did not give the ketene trimethylsilyl or methyl acetals. With diazomethane a bicyclic trienone 13 was formed, presumably by cyclopropanation